The invention concerns a gas valve, such as may be used in particular as a metering valve for a gaseous medium.
The invention is based on a gas valve as known for example from publication DE 10 2009 002 836 A1. Such a gas valve is used as a metering valve for a gaseous medium, for example for metering gaseous fuel to be supplied to an internal combustion engine. The known gas valve is here one which is operated electromagnetically and has a valve plate as a sealing element, which is arranged moveably within the gas valve relative to its axis of symmetry. The valve plate cooperates with a valve seat so that when the valve plate lifts away from the valve seat, an inflow cross-section is opened through which the gaseous medium can flow, wherein the metering takes place via the opening duration of the gas valve. The valve plate is moved via the force of an electromagnet which is switched on to open the gas valve and switched off to close the gas valve again, wherein closure of the gas valve takes place via a corresponding closing spring which pressurizes the valve plate.
The gaseous medium to be metered pressurizes the side of the valve plate facing away from the valve seat and leads to a closing force on the valve plate. This closing force must be overcome by the electromagnet which must lift the valve plate away from the valve seat. Since the gas pressure is not always the same, different opening forces are required, which makes it difficult to meter the gaseous medium since the opening force and hence the opening time depend on the gas pressure of the gaseous medium to be metered. In addition, with the known gas valve, the opening cross-section is limited, i.e. the cross-section which is opened by the movement of the valve plate and through which the gaseous medium flows. In particular in gas valves which meter a gaseous fuel in large engines, it is absolutely essential to introduce the necessarily large gas quantity in a metered fashion in as short a time as possible, in order to achieve a high performance of the internal combustion engine.